ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 207 



Incertae Sedis. 



Development of the Statoblasts of Bryozoa.* — Wolfgang von 

 Buddenbrock has made a careful study of the development of the stato- 

 blasts in Cristatella mucedo and Plumatella repens, in regard to which 

 Braem and Kraepelin have given discrepant account. The author's 

 results corroborate those of Braem in almost every particular. A useful 

 summary is given at the end of the paper, sketching the development of 

 the funiculus and the statoblasts, but it is too long to quote. 



Rotifera. 



Bdelloid Rotifera : a New Classification.! — D. Bryce puts for- 

 ward a new classification intended to substitute for that hitherto current 

 an arrangement based on the fuller knowledge of to-day. Without 

 discussing the relationship of the Bdelloida to other Rotifera, -he accepts 

 the position given them by Plate and by Wesenberg-Lund as con- 

 stituting an order of the sub-class Digononta (or two-ovaried Rotifera), 

 distinguishing them from the Seisouaceae by their ramate jaws, their 

 more or less effective rostrum, and their contractile cloaca. 



He divides the Bdelloida into three families : — 1. Philodinidse, 

 including all species with well-developed rostrum and corona, the latter 

 always capable of retraction within the mouth. 2. Adinetidse, including 

 all forms with imperfect rostrum, and a corona which cannot be retracted 

 within the mouth. 3. Microdinidae, including species possessing a 

 rostrum but without a corona. 



It is pointed out that in being able to creep about without the use 

 of the corona the Philodinidae differ not onlv from the Adinetidas, but 

 also from all other members of the class Rotifera. 



The family Philodinidae comprises nearly 100 recognized species 

 which, with few exceptions, conform closely in most respects to one 

 structural plan. The primary and most important distinction is based 

 on the proportion of the lumen, or cavity of the lining membrane of the 

 stomach, to the cavity of the outer or enclosing membrane. It is found 

 that in about one-fourth of the species the lumen is nearly as great as 

 the cavity of the outer membrane, whilst in the remaining three-fourths 

 it is relatively small. The Philodinidae divide thus into two sections, 

 having respectively a wide and a narrow lumen of the stomach. From 

 consideration of the greater average size, the great proportional develop- 

 ment of the corona (and especially of the trochal disks), and of the 

 greater activity, mobility and boldness of the species which have a 

 narrow lumen, the author believes that these represent a later stage in 

 evolution of the family type than that indicated by the species with a 

 wide lumen. 



The latter group is represented by three genera : — 1. Habrotrocha 

 L r . n., corona of normal type. 2. Ceratotrocha g. n., corona having two 



* Zeitschr. wiss. Zool., xcvi. (1910) pp. 477-524 (3 pis. and 8 figs.). 



t Jouni. Quekett Micr. Club, Ser. 2, xi., No. 67, Nov. 1910, pp. 61-92 (1 pi.). 



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